To make the 300mm telephoto focal length more fun and accessible, Tamron focused intently on designing a telephoto zoom lens that’s both small and lightweight. Turning the conventional concept of a telephoto lens on its head, the 70-300mm F4.5-6.3 is only 148mm (5.8 in) in length with a maximum diameter of 77mm and a weight of just 545g (19.2 oz). This gives users the freedom to concentrate fully on shooting without worrying about lens size or weight. In addition to those wishing to pursue real telephoto shooting for the first time, the lens is also recommended for people who use cameras that have built-in image stabilization because they can leave the tripod at home.

The 70-300mm F4.5-6.3 zoom’s optical design was refined via thorough simulations utilizing the latest technologies. With high priority on reduced size and weight, Tamron selected the aperture of F6.3 for the telephoto end to achieve a slim lens barrel and outstanding lightness. Taking the weight savings even further, we used a specially treated, high-strength aluminum-magnesium alloy3, the first time Tamron has used this material in the mount components of a lens for full-frame mirrorless cameras. The new design maintains excellent strength while successfully reducing weight to around 68% of previous mounts. The lens is made up of 15 elements in 10 groups with an appropriate arrangement of LD (Low Dispersion) lens elements.

The AF drive on the 70-300mm F4.5-6.3 includes an RXD motor unit to help you stay focused on the action. RXD uses an actuator to precisely control the rotational angle of the motor, allowing it to directly drive the focusing lens without passing through a reduction gear. A sensor that precisely detects the position of the lens enables high-speed and accurate AF, which is ideal when shooting continually moving subjects or recording video. And with a focusing system that is both smooth and quiet, the 70-300mm F4.5-6.3 lets you shoot free from stress not worrying the drive sound in a quiet environment.